if you are using clones you might not want to put them outdoors as early as march you would probably be better off waiting till mid april as the dark hours in march might actually be long enough to confuse the plant into starting flowering and then have to reveg as the dark hours decrease, wich actually slows its growth as it reverts back to a veg state.
might take clones around late feb to early march and veg indoors for a month then move them outdoors while you could start earlier if you wish but dont think it would help your plants to yield much more, think genetics and growing conditions will play a more improtant role in yield per plant.